Tobacco Thrips

May 9, 2008

Tobacco Thrips

DESCRIPTION Adults: The female tobacco thrips is dark brown or black, slender, and about
1 mm long. Each 8-segmented antenna has several yellowish middle segments; the rest of the
segments are much darker. Males are usually yellow.

Eggs: The white egg cannot usually be seen because it is inserted into the plant tissue.

Larvae: Both stages of tobacco thrips larvae are very light yellow.

Prepupae and Pupae: After the larval stages, tobacco thrips develop through two resting
stages, the prepupa, and pupa. Each stage is yellowish and sluggish. These stages are
spent in a close hiding place, usually on the ground. The antennae are directed toward
the front of the insect in the prepupal stage and are held back over the head and thorax in the pupal stage.
BIOLOGY Distribution: This thrips is found throughout the United States and Canada east of the Rocky Mountains.

Host Plants: Many plants are attacked by the tobacco thrips, especially gladioli,
many ornamentals, cotton, and peanuts.

Damage: Plants infested with tobacco thrips have silvery outlines traced around the veins,
and if the damage is severe, the leaves become yellow. These thrips also leave small black
spots on the underside of the leaves.

Life Cycle: In greenhouses and on field-grown flowers, the tobacco thrips is most often found
in the fall. This insect is often mistaken for the much more destructive gladiolus thrips;
however, the tobacco thrips adult is larger and the antennae are lighter in color than those of the gladiolus thrips.

As is common for many thrips, the tobacco thrips can reproduce parthenogenically, but males
are usually present. Eggs are inserted completely into the leaves. In 6 days the eggs hatch
into active young. Two larval stages, a prepupal and a pupal stage, occur within 2 weeks.
An entire life cycle can be completed in about 18 days. Adult thrips live 3 to 5 weeks,
and each female deposits about 55 eggs during this time. The adults will have either long or short wings.
The long-winged forms usually appear in late spring outside and migrate to a new host. Outside,
the tobacco thrips overwinter as short-winged adults in sheltered areas. Excessively rainy
conditions reduce the thrips population. Usually the tobacco thrips are not found grouped
together in folded leaves or under the bracts of the flower spikes as are gladiolus thrips.

Written by Mike · Filed Under Pests